Lindfield had put the hosts in but were very much up for the challenge as Bret Silvey (128) and Scott Clark (91no) took them close at 315-6.
That was about as good as it got for the Mid Sussex contingent for there were defeats for Ansty and Burgess Hill, while Keymer & Hassocks would have been disappointed not to beat lowly Crawley.
Jamie Tullett took 4-47 to restricted Keymer & Hassocks to 206-8 and then 50 from Paul Clifford enabled the visitors to hold on at 198-9.
Brad Holt hit 99 and Neil Priddy 66 not out for Sidley in a total of 272-4 before they bowled out visiting Ansty for 226. Daniel Belfort (82) was an unlucky loser.
Ben Hopkins made 84 for Burgess Hill in a total of 221-8 declared but it proved totally inadequate as visitors Chiddingly cruised to victory at 222-3, with Ken Ramsey making 138 not out.
Seaford lead the division by 60 points after making it seven wins in eight. They were six-wicket winners at Hellingly after the home side mosted a more than respectable 227-7 thanks mainly to Scott Pearce (75) and Justin Rosenburg (59). Stuart Pulford took 4-48.
In reply the leaders made 231 for 4 with 103 not out from Kylin Varhan and 79 from Adam Kneller.
Henfield continue to struggle in the West Division although it was close at Pagham despite them batting first and making only 117 all out. The hosts finally got hime by three wickets.
Billingshurst top the table after winning by 134 runs at home to Findon. John Burroughs hit 138 and Andrew Simmons 55 not out to take the hosts to 256-4 and in reply Findon were dismissed for 122 as Carleon Broome took 5-29.
Steyning won by seven wickets at Goring after bowling out the home side for 166, of which Sam Botham made 51. Bill Buckley hit 67 in the successful chase.
Ifield held on for a draw at Bognor after the hosts had set them 257-7 thanks to Rob Willway (61no), Luke Seward (58) and Phil Ball (53). Peter Dickson was top scorer in the Ifield reply of 206-8.
Arundel enjoyed a 29-run home win against Slinfold after posting 198-8. In the Slinfold reply of 169 all out, John Augustus hit 80 as Rakesh Parmar took 6-62.
Amazingly, the Lindfield/Uckfield 2nd XI games was similar to the 1st team clash although this Lindfield completed a successful run chase after a big century from one of the Uckfield batsmen.
Colin Toovey hit 141 to lead the visitors to a formidable 257-5 declared but Lindfield got home by two wickets thanks in part to Peter Newman (59) and Malcolm Page (56).
East Division: *Burgess Hill (11) 221-8dec (Ben Hopkins 84) lost to Chiddingly (28) 222-3 (K Ramsey 138no); Hellingly (12) 227-7dec (Scott Pearce 75, Justin Rosenburg 59) lost to *Seaford (24) 231-4 (Kylin Varhan 103no, Adam Kneller 79); Keymer & Hassocks (14) 206-8dec drew with *Crawley (10) 198-9 (Paul Clifford 50); Sidley (30) 272-4dec (Brad Holt 99,Neil Priddy 66no) *Ansty (5) 226 (Daniel Belfort 82); Uckfield (13) 318-7dec (A Gleeson 157no) drew with *Lindfield (9) 315-6 (Bret Silvey 128, Scott Clark 91no). West Division: *Arundel (28) 198-8dec bt Slinfold (11) 169 (John Augustus 80, Rakesh Parmar 6-62); Billinghurst (30) 256-4dec (John Burroughs 138, Andy Simmons 55no) bt *Findon (1) 122 (Carleon Broome 5-29); *Bognor (14) 257-7dec (Rob Willway 61no, Luke Seward 58, Phil Ball 53) drew with Ifield (11) 206-8 (P Dickson 66); Goring (7) 166 (Sam Botham 51) lost to *Steyning (30) 170-3 (Bill Buckley 67); Henfield (3) 117 lost to Pagham (30) 118-7.
2nd XIs, East: Burgess Hill (30) 126 bt Chiddingly (10) 111; Seaford (13) 261-5dec (Jacob Miles 75, James Mason 73) drew with Hellingly (9) 226-7 (S March 50); Crawley (13) 246-8dec drew with Kaymer & Hassocks (11) 177-7; Sidley (6) 137 lost to Ansty (30) 140-8; Uckfield (14) 257-5dec (Colin Toovey 141) lost to Lindfield (20) 260-8 (Peter Newman 59, Malcolm Page 56).
2nd XIs, West: Arundel (30) 308-8dec (A Johnson 118, J Murray 82) bt Slinfold (7) 144; *Billingshurst (24) 159 (Adrian Dudman 56) bt Findon (12) 149; Ifield (30) 234-5dec (Stuart Constable 103no) bt Bognor (5) 135; Goring (3) 137 lost to *Steyning (30) 138-3; *Henfield (28) 195-9dec (Wayne Harrison 64no) bt Pagham (10) 148 (Joe Metz 80).
Fixtures for Saturday June 27, East Division: Crawley v Burgess Hill; Lindfield v Keymer & Hassocks; Seaford v Chiddingly; Sidley v Uckfield Anderida; Ansty v Hellingly. 2nd XIs reversed.
West Division: Arundel v Bognor Regis; Henfield v Billingshurst; Ifield v Pagham; Slinfold v Goring-by-Sea; Steyning v Findon. 2nd XIs reversed.