The same rules apply for soletraders, partnerships and Limited Companies.
You can entertain your clients and woo potential clients to your heart’s content, but the expense is not allowable against profits and any such expense that your business incurs during a financial year are adjusted for on the final tax calculation. This may seem unfair – you could claim all such expenses back at one time, but people started to get silly ( taking clients to expensive football/golfing matches for example) so the Revenue responded by disallowing everything.
VAT considerations: you cannot claim the VAT back on client entertaining either.
Entertaining you staff is a different matter. Anything you spend on your staff to give them a Christmas party, or an annual business birthday party etc is claimable against profits and all VAT can be claimed back. People are usually advised to keep such expenditure to below £150 per head per annum, as this causes benefit-in-kind’ issues.
What You Can Claim As Business Expenses main page.